A Simple Method for the Biodiesel Production by the Reuse of Different Types of Waste Frying Oils

Abstract

A simple and complete method for the production and characterization of methylic and ethylic biodiesel from the main types of waste frying oils produced in Brazil was developed. The waste frying oils of soybean, canola, corn and sunflower were employed in the production of methylic and ethylic biodiesel by transesterification reaction via basic homogeneous catalysis. The transesterification reactions were performed at 40oC during 40 min, using a catalyst percentage (KOH) equal to 2%. After separation of the phases biodiesel/glycerol, biodiesel was washed with 0.1M HCl aqueous solution, heated at 100 oC to remove excess alcohol and finally filtered under vacuum with silica, a drying agent. The reaction yields were in the range 67.8-95.9%, quite satisfactory. The oxidative stability index was obtained for the oils as well as the biodiesel. Quality control of the original oil and of the methylic and ethylic biodiesels was accomplished by the TLC and GC-MS techniques. The results presented indicate the main waste frying oils produced in Brazil as potential sources of feedstocks for biodiesel production, which could aid in the development of the local cities that adopt programs to collect and reuse of waste oils. Furthermore, we emphasize that was obtained a route for biodiesel production greener, producing a biofuel substituent to mineral diesel by the reuse (or recycling) of waste. Key words : Methylic biodiesel; Ethylic biodiesel; Waste frying oils